Water base lubricant



United States Patent 3,404,090 WATER BASE LUBRICANT Roy J. Betty,Chicago, Ill., and Robert E. Malec, Birmiugham, Mich., assignors toArmour and Company, Chicago, 111., a corporation of Delaware No Drawing.Feb. 14, 1967, Ser. No. 615,924 4 Claims. (Cl. 252-475) ABSTRACT OF THEDISCLOSURE A pyrimidine thione and amine oxide composition for use as aWater base lubricant and a process for imparting lubricity to aqueoussystems.

BACKGROUND OF THE INVENTION This invention pertains to a compositioncomprising an N-secondary-aliphatic-hexahydropyrimidine-2-thione, and abis(Z-hydroxyethyl) aliphatic amine oxide; and a process utilizing saidcomposition for imparting lubricity to aqueous systems.

In various fields where lubricants are required, it has been found thatorganic oils are not completely satisfactory. For example, in secondaryoil recovery systems, wherein 'water is pumped into the ground to forceoil to the surface, there is a tendency for oil lubricants to plate outupon the pump. Further, when oils are used as cutting fluids,considerable time is often spent in removing the oils from the product.In addition, organic oils may present a fire hazard, they often formemulsions, and they may not be compatible with other additives to thewater systems. Also organic oils, such as mineral oil, tend to loselubricity under certain light and pressure conditions.

Recently, a water base lubricant comprising water andbis(Z-hydroxyethyl) aliphatic amine oxides has been disclosed.

SUMMARY OF II-IE INVENTION We have discovered that combiningbis(2-hydroxyethyl) aliphatic amine oxides with N-secondary-aliphatichexahydropyrimidine-Z-thiones results in a composition exhibitingsynergistic water soluble lubricity. We were surprised to find that thiscombination imparts water soluble lubricant properties greater thanWould be expected if the compounds acted independently when used at thesame total quantitative amounts. It should be understood thatsynergistic activity is a relatively rare and unexpected occurrence.Further, our synergistic composition is noninflammable and is compatiblewith organic additives such as antifreeze materials, corrosioninhibitors, thickeners, and other desirable additives to the water. Inaddition, organic oils may be omitted from our process for impartinglubricity to water systems, thereby there is no danger of rancidity,forming of sludge or other degradation products.

3,404,090 Patented Oct. 1, 1968 DETAILED DESCRIPTION OF THE INVENTION Aspecific embodiment of our invention may be exemplified by thecomposition comprising (A) N-(C- -Csecalkyl)hexahydropyrimidine-Z-thione and (B)bis(2-hydroxyethyl)cocoamine oxide. While substantial synergisticlubricity is exhibited when the proportions by weight of component (A)to component (B) of this composition range from about 1:5 to about 5:1,particularly desirable results are obtained as the proportions approach1:1, such as at 3:1, 1:3, 2:1, 1:2 and 1:1. It will be understood thatproportions outside this range will exhibit some degree of lubricity.

In another embodiment of our invention, we introduce into water at least20 parts, per million parts of water by weight, of (A) anN-sec-alkyl-hexahydropyrimidinc-2- thione wherein the secondary-alkylradical contains from 6 to 15 carbon atoms and (B) a bis(Z-hydroxyethyl)aliphatic amine oxide wherein the aliphatic radical contains from 6 to22 carbon atoms, the proportions of (A) to (B) being as illustrated forthe composition set forth hereinabove. A preferred concentration of thepyrimidine thione and amine oxide composition is about 50 to parts ofthe composition per million parts of water, and the upper limits of thisconcentration do not appear critical. We may use 500 parts of the amineoxide-pyrimidine thione compositions, or more, per million parts ofwater.

Illustrative amine oxides having utility as one component in ourcomposition have the structure FORMULA I CH CH OH CHgCHzOH wherein R isan aliphatic hydrocarbon radical containing from 6 to 22 carbon atoms. Rmay be straight or branched chain, saturated or unsaturated groups suchas octyl, nonyl, N-(C -C sec-alkyl), dodecyl, tridecyl, tetradecyl,pentadecyl, N-(C C sec-alkyl), hexadecyl, octadecyl, octadecenyl,octadecatrienyl, docosyl, eicosyl, and mixtures of radicals such as arederived from naturally occurring glycerides such as coconut oil, tallow,soybean oil and the like. Coconut oil contains a mixture of saturatedand unsaturated aliphatic hydrocarbon radicals from C to C and isprimarily N-dodecyl. Tallow contains a saturated and unsaturated mixturefrom C to C primarily N-hexadecyl, N-octadecyl and octadecenyl. Soybeancontains a saturated and unsaturated mixture from G to C primarilyoctadecenyl and octadecadienyl.

The preparation of useful bis(Z-hydroxyethyl) aliphatic amine oxides maybe by the reaction with an excess of hydrogen peroxide as is known inthe art.

Exemplary N-sec-alkyl hexahydropyrimidine-Z-thiones useful as the secondcomponent of our synergistic combination have the structure FORMULA IIwherein R is an individual or mixed chain length N-secondary-alkylradical having from 6 to 15 carbon atoms. These compounds may beprepared by reacting a thiocarbonyl group containing compound, such ascarbon disulfide, thiophosgene, ethylene trithiocarbonate, and the likematerials, with a long chain diamine in a mutual solvent, such asmethanol, ethanol, isopropanol, butanol, chloroform, ethylene chloride,carbon tetrachloride, ether and the like materials at temperatures of to80 C. Some useful diamines for this preparation have the followingstructure:

FORMU LA II I H II]: RI IC Hz 0 Hz 0 Hr-N-H wherein R is a secondaryalkyl radical having from 6 to carbon atoms. Initially, thedithiocarbamic acid inner salt is formed which, upon further heating at90 to 200 C. gives olT hydrogen sulfide with formation of the cyclichexahydropyrimidine-2-thione.

When the composition has been prepared as above described, otheradditives may be included in the water system. For example, lowmolecular weight glycols or alcohols, such as ethylene glycol, propyleneglycol, etc., or methanol, ethanol, etc., may be added as antifreezematerials. Carboxymethyl cellulose, alginates, etc. may be added asthickeners. Similarly, water corrosion inhibitors may be added. Theforegoing additives are compatible with the water base lubricant. Ifdesired, they may be omitted.

Comparative evaluations of the amine oxides and pyrimidine thiones asdescribed herein show that these compounds exhibit greater lubricity incombination than would be expected if the compounds acted independently.A specific comparison is set out in the accompanying examples, which areillustrative of our composition and process.

Example I Equimolar amounts of a mixture of long chain C to Csecondary-alkyl diamines and carbon disullide ar admixed with coolingand stirring while both are dissolved in ethanol. The ethanol solutionof each comprises a 50% by weight solution. A temperature of 30 C. isutilized as the reaction temperature. A mixture of N-(C -C secalkyl) 1,3propanediamine N dithiocarbamic acids is formed. The acids ar thenremoved from the alcoholic media by evaporation and heated at atemperature of 115 C. to cause evolution of H 8. This causes cyclizationto N (C -C sec alkyl)hexahydropyrimidine 2- thione.

Example II A convenient and meaningful method of measuring water solublelubricity is by means of a Baroid extreme pressure mud tester, which issimilar to a Timken wear tester. A standard evaluation procedure isfollowed where in the test cup and the test block are weighed to thenearest rng.; then the test cup is mounted on the beveled ring locatedon the bottom of the belt driven shaft and the test block is mounted atthe bottom of the shaft connected to the torque arm. The samplecontainer is filled with approximately 200 ml. of a brine solution ortap water with the desired amount of the chemical to be evaluated. Afterthe sample cup is positioned so that the test cup and test block arecovered with fluid, the motor is started and the machine allowed to run5 minutes with no load applied. The load test evaluation is then startedat lb. load and taken up to 140 lb. load in 20 lb. increments at 5minute intervals. The wear test evaluation is the same evaluationinitially, with a continuation of running the machine at 140 lb. loadfor minutes. At the end of the evaluation test periods, the test cup andblock are removed, rinsed, and reweighed. The weight loss (amount ofwear) indicates the efficiency of the lubricant. If galling or seizingoccurs during the evaluation, the machine is stopped. The brine solutionused in some of the evaluations following herein consisted of water,10.5% sodium chloride, 9.4% calcium chloride, 0.06% magnesium chloride,0.02% ferric chloride, and 0.02% sodium sulfate.

Illustrative results comparing a known water soluble lubricant andcertain of the components of this invention, individually and combined,are set forth in Table I. The chemicals designated in the table aredefined as follows:

Aromox C/ 12 is bis(Z-hydroxyethyl)cocoamine oxide Aromox T/ 12 isbis(2-hydroxyethyl)tallowamine oxide NL-7 PTU is N-(C Csec-alkyl)hexahydropyrimidine- Z-thione NL-ll PTU is N-(C Csec-alkyl)hexahydropyrimidine-Z-thione.

TABLE I Chemical Concentration, Wear in mg.

p.p.m. weight loss Load test in brine:

Standard 1 300 41. 3 200 10. 8 Aromox C/12 1 8 555 0 25. 7 7 PTU 50 13.9NL-ll PTU 19.8 Aromox O/12 100 1 and 2. 2 NL- PTU 50 1 Load test intapwater:

Aromox 0/12 200 55.5 NL-7 PTU 100 30.0 Aromox 0/12 100 and 10.2 NL-7 PTU50 Wear test in brine:

Aromox 0/12 100 and 2.1 NL-7 PTU 50 A water base lubricating productprimarily containing a methyl ester of alpha sulio stcaric acid.

Example III Illustrative proportions and concentrations showing theenhanced water base lubricity of the composition are set forth in thefollowing additional load test results obtained by the procedures ofExample II:

While in the foregoing specification, we have described specificcompositions and procedures in considerable detail for the purpose ofillustrating our invention, those skilled in the art will appreciatethat variations can be made without departing from the spirit and scopeof our invention; and therefore, it is not intended to be limited exceptas indicated in the appended claims.

We claim:

1. A composition comprising anN-secondary-aliphaticl1exahydropyrimidine-Z-thione wherein thesecondaryaliphatic radical contains from 6 to 15 carbon atoms and abis(2-hydroxyethyl) aliphatic amine oxide wherein the aliphatic radicalcontains from 6 to 22 carbon atoms, and in which the proportions byweight of the pyrimidine thione to the amine oxide range from about 1:5to about 5:1, said composition displaying synergistic lubricity whenused with water in a concentration of at least 20 ppm.

2. The composition of claim 1 in which said pyrimidine thione is N-(C Csec-alkyl)-hexahydropyrirnidine-2- thione and said amine oxide isbis(2-hydroxyethyl)cocoamine oxide and said proportion is about 2:1.

3. The composition of claim 1 in which said composition displayssynergistic lubricity when used with brine in a concentration of atleast 20 p.p.m.

4. The composition of claim 3 in which said pyrimidine thione isN-(Cq-Cg sec-alkyl)hexahydropyrimidine-Z-thione and said amine oxide isbis(2-hydroxyethyl)cocoamine oxide and said proportion is about 1:2.

6 References Cited UNITED STATES PATENTS 3,108,071 10/1963 Harker 25247X 3,346,495 10/1967 Malec et a1. 252-49.3

PATRICK P. GARVIN, Primary Examiner. W. H. CANNON. Assistant Examiner.

